IEC 60079-14 Best Practices: What to Check Before an Ex Installation Is Accepted
Checking Ex equipment, cable entries, certification, and installation details before acceptance.
Installing electrical equipment in a hazardous area involves more than mounting certified Ex equipment and connecting the cables. Equipment suitability, installation methods, cable entries, protection concepts, and supporting documentation must be reviewed together.
IEC 60079-14 addresses the design, selection, and erection of electrical installations in explosive atmospheres, including requirements related to initial inspection. This guide provides a practical checklist for engineers, contractors, inspectors, and procurement teams reviewing an Ex installation before acceptance.
1. Confirm the Hazardous Area Classification
Start by confirming the hazardous area in which the equipment will operate. Identify the applicable zone or other area classification and determine whether the potential explosive atmosphere involves gas, vapour, mist, or combustible dust.
Verify that the selected equipment is suitable for the classified area and the required level of protection. Do not select equipment based only on voltage, power rating, enclosure size, or availability.
Acceptance check: Confirm that the area classification documentation and equipment selection are consistent.
2. Verify the Ex Equipment Marking
Ex equipment must be suitable for its intended application. Review the complete marking rather than checking only for the presence of an Ex symbol.
- Protection concept, such as Ex d, Ex e, or Ex i, where applicable
- Equipment group and gas or dust group, as applicable
- Temperature class or maximum surface temperature
- Equipment Protection Level (EPL) or applicable equipment category
- Ambient temperature range
- Certificate number and manufacturer identification
- Special conditions of use, where applicable
Acceptance check: Compare the equipment marking with the hazardous area requirements, project specifications, and applicable equipment documentation.
3. Match the Equipment to Its Certificate
A certification document should correspond to the actual equipment supplied. Similar product names or model numbers do not necessarily mean that different variants have the same certification or ratings.
Compare the following information:
- Manufacturer and model or type designation
- Ex marking and certificate number
- Electrical ratings and applicable environmental limits
- Certificate conditions and any referenced installation instructions
Review any special conditions of use before installation. Depending on the certified design, these may address cable or gland arrangements, mechanical protection, ambient temperature, electrostatic considerations, installation orientation, or other limitations.
Acceptance check: Resolve discrepancies between the supplied equipment, certificate, and documentation before accepting the installation.
4. Verify Cable Gland Selection
Cable gland selection should not be based on conductor size alone. The cable's actual construction and dimensions can affect gland suitability.
Depending on the cable and application, check:
- Cable outer diameter and relevant sheath or bedding dimensions
- Armour type and arrangement, where applicable
- Cable construction against the gland manufacturer's specified range
- Gland suitability for the equipment's protection concept
- Thread type and size at the enclosure entry
Acceptance check: Confirm that the selected gland is suitable for the actual cable, enclosure, and Ex application. Follow the manufacturer's installation instructions.
5. Inspect Cable Entries and Sealing Arrangements
The cable entry is part of the installed protection system. A suitable gland does not guarantee a compliant installation if the entry is incorrectly assembled or incompatible with the enclosure.
Review the compatibility of the enclosure, gland, cable construction, sealing arrangement, thread connection, and earthing or bonding provisions where applicable.
Also check unused entries. They must be closed using suitable components compatible with the equipment and its protection requirements.
Acceptance check: Verify that cable entries, glands, stopping or sealing arrangements where required, and unused-entry closures are correctly selected and installed.
6. Check Installation Details for the Protection Concept
Different explosion protection concepts have different installation requirements. For example, installation details for an Ex d flameproof enclosure are not interchangeable with those for Ex e increased safety equipment.
Review the actual protection concept shown on the equipment marking, then check the installation against the applicable requirements and manufacturer instructions. Pay particular attention to cable entries, enclosure joints and covers, fasteners, and other features relevant to the protection concept.
Acceptance check: Confirm that the installed arrangement is appropriate for the specific certified equipment—not merely for Ex equipment in general.
7. Inspect Mechanical Condition and Mounting
Equipment that is electrically connected and operational is not automatically ready for acceptance. Mechanical defects or incorrect assembly can compromise the equipment's intended protection.
- Inspect the enclosure for damage or unauthorised modifications.
- Check covers, fasteners, and entry closures.
- Verify gland installation and mechanical support.
- Check protection against foreseeable physical damage.
- Confirm the specified mounting orientation and clearances, where applicable.
- Verify earthing and bonding connections where required.
Acceptance check: Record defects and resolve them before the installation is accepted.
8. Complete the Initial Inspection Before Acceptance
Mounting and energising equipment are not substitutes for the required inspection. The completed installation must be assessed against the applicable requirements, design information, equipment documentation, and hazardous area classification.
The inspection scope and method should follow the applicable edition of IEC 60079-14 and the project's inspection requirements. A visual review alone may not be sufficient for every installation or inspection item.
Acceptance check: Confirm that the required initial inspection has been completed, findings have been recorded, and outstanding defects have been addressed through the project's formal process.
9. Verify Documentation and Traceability
Installation records help demonstrate that the equipment installed in the field matches the approved design and supporting certification. They also support future inspection, maintenance, and modification.
Depending on the project requirements, records may include:
- Hazardous area classification drawings and documents
- Equipment schedules and datasheets
- Ex certificates and manufacturer's instructions
- Cable and cable gland details
- Installation and inspection records
- Records of defects, corrective actions, and acceptance
Acceptance check: Maintain traceability between the installed equipment, its identification, the relevant certification, and the inspection records.
Practical Ex Installation Acceptance Checklist
Use this table as a starting point for an installation review. The actual inspection checklist must be adapted to the equipment, protection concepts, site conditions, and applicable project requirements.
| Inspection item | What to verify | Status |
|---|---|---|
| Hazardous area | Equipment is suitable for the documented area classification. | Pass / Fail / N/A |
| Equipment marking | Protection concept, group, temperature rating, EPL or category, and ambient range are suitable. | Pass / Fail / N/A |
| Certification | Model, marking, certificate, and relevant conditions are consistent. | Pass / Fail / N/A |
| Cable gland | Gland is suitable for the actual cable, enclosure, and protection concept. | Pass / Fail / N/A |
| Cable entries | Threads, sealing arrangements, and unused-entry closures are suitable and correctly installed. | Pass / Fail / N/A |
| Special conditions | Applicable certificate conditions and manufacturer instructions have been followed. | Pass / Fail / N/A |
| Mechanical condition | Enclosure, covers, fasteners, mounting, and mechanical protection are acceptable. | Pass / Fail / N/A |
| Earthing and bonding | Required connections and continuity arrangements have been verified. | Pass / Fail / N/A |
| Initial inspection | Required inspection is complete and findings are documented. | Pass / Fail / N/A |
| Documentation | Equipment identification, certificates, installation records, and inspection findings are traceable. | Pass / Fail / N/A |
Common Mistakes to Avoid
- Selecting equipment based only on electrical ratings without checking area suitability.
- Checking the Ex marking but not verifying the relevant certificate and conditions.
- Selecting a gland from nominal cable size without checking actual cable construction.
- Ignoring thread compatibility or the requirements for unused entries.
- Applying the same installation method to different protection concepts.
- Assuming that certified components automatically make the complete installation compliant.
- Leaving inspection records and certification checks until the end of commissioning.
Conclusion
Acceptance of an Ex installation requires more than confirming that the equipment carries an explosion protection marking and has been installed. The equipment must be suitable for the hazardous area, correctly identified and certified, installed according to the applicable requirements, and supported by appropriate inspection records.
A structured review helps identify mismatches and installation defects before they lead to commissioning delays, inspection findings, or costly corrective work.
Important Note
This article is a practical reference and does not reproduce or replace IEC 60079-14. Verify all acceptance criteria against the applicable edition of the standard, project specifications, equipment certificates, manufacturer instructions, and local regulations.
Sources
- IEC 60079-14 — Explosive atmospheres — Part 14: Electrical installation design, selection and erection.
- IEC 60079-0 — Explosive atmospheres — Part 0: Equipment — General requirements.
- IECEx — International Electrotechnical Commission System for Certification to Standards Relating to Equipment for Use in Explosive Atmospheres.
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